Strongest counties and county-equivalents

[Verily]

Obama
District of Columbia: 92.46%
Prince George's County, MD: 88.90%
Shannon County, SD: 88.69%
Petersburg City, VA: 88.64%
Bronx County, NY: 88.46%

McCain
Much more difficult to find, but I think this is complete. Let me know if not.
King County, TX: 92.64%
Roberts County, TX: 92.08%
Ochiltree County, TX: 91.70%
Glasscock County, TX: 90.13%
Beaver County, OK: 89.25%

[Nym90]

Obama
District of Columbia: 92.46%
Prince George's County, MD: 88.90%
Shannon County, SD: 88.69%
Petersburg City, VA: 88.64%
Bronx County, NY: 88.46%

McCain
Much more difficult to find, but I think this is complete. Let me know if not.
King County, TX: 92.64%
Roberts County, TX: 92.08%
Ochiltree County, TX: 91.70%
Glasscock County, TX: 90.13%
Beaver County, OK: 89.25%

https://uselectionatlas.org/RESULTS/stats.php?year=2008&f=1&off=0&elect=0

Very well done nonetheless.

[Husker]

Wow, the third district of Nebraska wasn't in the Top 5 for McCain? I think Hell must be freezing over!

[Alcon]

Wow, the third district of Nebraska wasn't in the Top 5 for McCain? I think Hell must be freezing over!

There's still a lot of states where there's no CD information out yet, Nebraska included.  The early congressional district results had McCain leading NE-3, 68.7% to 29.5%.  That's probably tightened some, and either way, NE-3 is off McCain's top list.

Wasn't top five in 2004, either.

[NOVA Green]

Wow, the third district of Nebraska wasn't in the Top 5 for McCain? I think Hell must be freezing over!

There's still a lot of states where there's no CD information out yet, Nebraska included.  The early congressional district results had McCain leading NE-3, 68.7% to 29.5%.  That's probably tightened some, and either way, NE-3 is off McCain's top list.

Wasn't top five in 2004, either.

Although Arthur Co, Nebraska (CD-3) was in the top five counties for Bush in '04...

[Husker]

Many of the counties in north central and western Nebraska (known to Nebraskans as the Sand Hills) have less than 1,000 residents and less than 500 people voting. If you look at the election explorer on the NY Times and play around with population density, you will see that most of this state drops out by 5 people per square mile and is almost empty by 20 people per square mile. I guarantee you almost everyone who is voting in some of the counties is white and involved in ranching in some way, hence the republican domination. 20-25% for a democrat out there is very good... sad as that sounds.